Two die process

ABSTRACT

A closure panel forming and assembly process includes inputting partially stamped inner and outer panels into the assembly system and finished assemblies out. The invention is a manufacturing process for closure panel assemblies, doors, deck lids, hoods, liftgates and other similar panels. The process has a reduced stamping operation of only two die stages, with the first operation being a draw operation followed by a second operation of trim and pierce. These operations may be done at a satellite location which may be within the same facility or at an outside location. All additional metal forming operations are done at an assembly system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Patent Application No. 61/010,613 filed Jan. 10, 2008.

TECHNICAL FIELD

This invention relates to manufacturing processes for automotive closure assemblies, either steel or aluminum panels, or similar.

BACKGROUND OF THE INVENTION

It is known in the art relating to closure panel assemblies that stamping processes are traditionally 100% completed prior to bringing parts into the assembly system. However, when the stamping and assembly processes are located at different sites and the stamping steps include flanging for later hemming, the number of flanged panels that can be carried by the racks or other transport devices are significantly reduced relative to racks for blank panels. This increases costs for additional dunnage racks, increased transport trips and added storage area for the additional racks required.

SUMMARY OF THE INVENTION

The present invention provides a process of inputting partially stamped inner and outer closure panels into an assembly system and outputting finished assemblies. The invention comprises a manufacturing process for closure panel assemblies, doors, deck lids, hoods, liftgates and other similar panels. The process has a reduced stamping operation of only two die stages, with the first operation being a draw operation followed by a second operation of trim and pierce. These operations may be done at a satellite location which may be within the same facility or at an outside location. All additional metal forming operations are done at an assembly system. Without part flanging occurring in the stamping operation, part storage rack density will increase significantly.

The two die stamping operation provides for economically running small batches of parts to limit storage rack space requirements, increasing rack density of panels without flanging operation to as much as 50 to 120 panels within one dunnage rack. All additional forming operations outside of the two die operations will be completed in the assembly system. This significant increase in rack density is accomplished since traditional stamped panel dunnage racks have “slot” locations and flanging operations prevent stamped closure panels from being stacked.

With rack density increased, floor space required for storage of in-process material is reduced. Transportation of material between stamping operations and assembly operations is also reduced. Investment costs of dunnage racks from stamping operations are reduced through limited quantity of racks required. Investment costs of rack automation on the assembly system are eliminated with additional material available due to rack density. Assembly system plant floor space requirements are reduced without the need for multiple racks based on rack part density. Also, assembly system throughput efficiency increases with reduced change out frequency of empty racks.

With flange break line forming being done at the assembly system, the quality iteration process development will be of shorter duration with quick feedback from the assembly process.

These and other features and advantages of the invention will be more fully understood from the following detailed description of the invention taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view illustrating two die stamping operations at in-plant or outside satellite locations, and subsequent forming and assembly operations at the assembly plant;

FIG. 2 is a chart of production hours from one dunnage rack based on rack density and assembly system jobs per hour;

FIG. 3 is a chart of dunnage racks required to support four hours of production based on rack density and assembly system jobs per hour;

FIG. 4 is a schematic view of a prior art dunnage rack for flanged panels; and

FIG. 5 is a schematic view of a dunnage rack for non-flanged panels in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1 of the drawings in detail, numeral 10 generally indicates a method of two die forming operation. Method 10 is similar to traditional stamping operations in using multiple presses to serially perform forming and trim and pierce operations, but uses only two presses according to the invention rather than three or more. The method steps include:

1. Load blank panels 12 to draw press 14;

2. Form panels 12 in draw press 14;

3. Transfer formed panels to trim and pierce press 16;

4. Trim and pierce panels in press 16;

5. Unload partially stamped panels 17 to dunnage rack 18; and

6. Transport loaded dunnage rack 18 to assembly system initial station.

Numeral 20 generally indicates an alternative method of two die forming operation. Method 20 uses only a single press in which both forming and trim/pierce operations are performed in batch operations with separate dies. The method steps include:

1. Load draw die 22 to press 24;

2. Load blank panel 26 to press 24;

3. Form panel in press 24 with draw die 22;

4. Transfer formed panel to formed panel holding station 27;

5. Repeat steps 1-4 for all panels in batch;

6. Change out draw die 22 and load trim and pierce die 28 to press 24;

7. Load formed panel to press 24;

8. Trim and pierce formed panel in press 24 with trim and pierce die 28;

9. Unload formed and stamped panel 30 to stamped panel dunnage rack 32;

10. Repeat steps 7-9 for all panels in batch;

11. Transport loaded dunnage rack 32 with partially stamped panels 30 to assembly system initial station 34; and

12. Change out direct trim and pierce die 28 and load draw die 22 for processing a new batch of blank panels 26.

Numeral 36 indicates one exemplary method for completing forming and assembly of finished closure panels beginning at the assembly system initial station 34. The method 36 includes continuous forming and assembly steps to complete processing of the stamped panels from dunnage rack 18 or 32, loaded with identical two die processed panels from either one of the first or second optional two die methods 10 or 20. The continuing method steps include:

1. Loading serially the stamped panels 17, 30 at assembly system initial station 34 into a trim station 38;

2. Performing additional trim operations in station 38;

3. Transferring trimmed panels to a flanging station 40;

4. Performing flanging operations at the flanging station 40;

5. Transferring flanged panels and mating panels, not shown, into an assembly station 42;

6. Assembling the flanged and mating panels in station 42 by adding other necessary parts and hemming and welding the separate panels into completed closure assemblies, not shown;

7. Transferring the closure assemblies to an inspection station 44;

8. Inspecting the finished closure assemblies; and

9. Transferring the inspected closure assemblies to a transfer station 46 for shipping.

FIG. 2 is a chart 50 displaying hours of production from one dunnage rack (HPR) assuming an assembly system production rate of 30 to 90 gross jobs per hour (JPH) and a dunnage rack density (RD) of 50 to 120 two die stamped panels per rack. The charted production hours per rack vary between 0.56 HPR with 90 JPH production (rows) and 50 RD of panels (columns) and 4.0 HPR with 30 JPH production and 120 RD of panels.

FIG. 3 is a chart 52 displaying the number of dunnage racks (NR) required to support 4.0 hours of production assuming an assembly system production rate of 30 to 90 gross jobs per hour (JPH) (rows) and a dunnage rack density (RD) of 50 to 120 two die panels per rack (columns). The required number of racks (NR) charted varies between 8.0 NR with 90 JPH production (rows) and 50 RD of panels (columns) and 1.0 NR with 30 JPH production and 120 RD of panels.

FIG. 4 illustrates the prior art of a flanged panel 54 nested in a dunnage rack 55. The dunnage rack 55 typically includes slots 56 for the individual flanged panels 54 to rest in. The spacing of the slots 56 prevents the individual panels from contacting each other while in the racks. The flanges on the panels normally dictate the spacing between the panels in the racks, therefore limiting the number of flanged panels per rack.

FIG. 5 illustrates the dunnage rack 18 in accordance with the present invention for stamped panels 17 without flanges. Since the stamped panels 17 do not include flanges, the stamped panels 17 can be stacked one on top of the other, therefore providing for a greater number of panels per rack.

It should be apparent that without part flanging occurring in the stamping operations, part storage (dunnage) rack density will increase significantly. The number of dunnage racks requiring transport between the two die stamping site and the integrated forming and assembly site will thus be significantly reduced and the space required for storing dunnage racks will also be reduced resulting in substantial savings for the two die method of split site production of the present invention.

Although the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims. 

1. A split site forming and assembly process including the steps of: conducting first and second forming steps on panels at a forming site using two dies in at least one press, and loading the partially formed panels onto a dunnage rack, wherein no flanging of the panels is performed at the forming site; transporting the dunnage rack with the partially formed panels from the forming site to an assembly site; and loading the partially formed panels from the dunnage rack into a continuing forming and assembly operation at the assembly site.
 2. The process of claim 1 wherein the first and second forming steps are conducted with at least one forming press and two dies.
 3. The process of claim 2 wherein the first and second forming steps are conducted with first and second forming presses and a separate forming die in each press.
 4. The process of claim 3 wherein the first and second forming steps are conducted serially in the first and second presses.
 5. The process of claim 2 wherein the first and second forming steps are conducted in batches in a single press with die change out between the batches.
 6. The process of claim 2 wherein the first and second forming steps include a drawing step and a trim and pierce step.
 7. The process of claim 1 including further forming and assembly steps performed at the assembly site.
 8. The process of claim 6 including further forming and assembly steps performed at the assembly site.
 9. The process of claim 8 wherein the further forming and assembly steps include flanging and assembly steps.
 10. The process of claim 9 including a trim step prior to the flanging step and an inspection step subsequent to the assembly step.
 11. A split site forming and assembly process for forming closure panel assemblies, the process including: conducting first and second forming steps on outer panels with two dies in at least one press at a forming site and loading the partially formed outer panels onto a dunnage rack, wherein no flanging of the panels is performed at the forming site; transporting the dunnage rack with the partially formed outer panels from the forming site to an assembly site; loading the partially formed outer panels from the dunnage rack into a continuing forming and assembly operation at the assembly site; conducting additional forming steps including flanging of the outer panels at the assembly site; and conducting assembly steps including hemming of the outer panels to mating inner panels and fixing the outer and inner panels together to form closure assemblies.
 12. The process of claim 11 including a trim step prior to the flanging step and an inspection step subsequent to the assembly step.
 13. The process of claim 11 wherein the first and second forming steps are conducted with at least one forming press and two dies.
 14. The process of claim 13 wherein the first and second forming steps are conducted with first and second forming presses and a separate forming die in each press.
 15. The process of claim 14 wherein the first and second forming steps are conducted serially in the first and second presses.
 16. The process of claim 11 wherein the first and second forming steps are conducted in batches in a single press with die change out between the batches.
 17. The process of claim 13 wherein the first and second forming steps include a drawing step and a trim and pierce step. 